Distal protection device

ABSTRACT

A distal protection device provided with a filter basket having a self-expanding radial loop designed to position the filter basket within human vasculature and to hold the filter basket open during deployment.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a continuation of U.S. patent application Ser. No.10/823,139 by Oslund et al., filed on Apr. 13, 2004, which is a divisiondivisional of U.S. patent application Ser. No. 09/628,212, by Oslund etal., filed Jul. 28, 2000, now U.S. Pat. No. 6,740,061. The entirecontent of both U.S. patent application Ser. Nos. 10/823,139 and09/628,212 are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to devices deployable in a vessel of thebody such as a distal protection device deployable in a blood vessel. Inone of its more particular aspects, the invention relates to thepositioning of a guidewire or filter within human vasculature.

BACKGROUND OF THE INVENTION

Any intervention into human vasculature can give rise to the need forcapturing and retrieving debris, such as grumous matter, emboli, orthrombi, from the affected vessel. Filters of various types have founduse, for example, in trapping blood clots and other debris released intothe bloodstream. Many filters, however, can be only partially effectivein capturing the debris from surgical or catheterization interventionsbecause deployment of the filter within the blood vessel may not providecomplete filtration. That is, a filter may not effect filtration acrossthe full cross-section of the blood flow through the vessel. This mayresult from failing to maintain an optimum fit of the filter within thevessel wall. Where a filter basket is used, another cause for concern isthat the basket may not always be fully opened upon deployment withinthe vessel.

Specifically, filters are traps that have been designed to be used tocollect dislodged matter, such as grumous matter, emboli or thrombi,during procedures such as stent installation in coronary saphenous veingrafts. Such filters or traps serve to provide protection from distalembolization that might result in a major adverse coronary event orother acute complication. Embolization of debris which might be releasedduring such procedures and the resulting sequellae have been describedin reports documenting major adverse cardiac event rates. Such eventsinclude acute myocardial infarction, revascularization and even death.

In order to address such acute embolic-related complications, distalfiltration and protection devices have been developed. Such devices havebeen designed to work with existing interventional modalities. Suchdevices provide debris-filtering protection during invasive proceduresand are intended to prevent complications of particulate embolization.

Such distal filtration and protection devices are typically deployed ata location along a vessel of the body at a desired location. Suchdeployment is performed by extending the device outwardly from thedistal end of a catheter. In order to facilitate deployment, the deviceto be deployed typically has components made from a shape-memory orhighly elastic material. Consequently, they are able to be collapsedwithin the catheter and, upon being urged outwardly beyond the distalend of the catheter, they reassume their uncollapsed shape.

Nevertheless, performance of such filtration and protection devices isless than perfect. One significant drawback is the general lack ofrigidity of the device. While shape-memory materials are used and thedevice, once released from the catheter, tends to assume an intendeduncollapsed configuration, the path of the vessel within which it isintended to be installed can be tortuous. The guidewire upon which thedevice is installed, therefore, tends to alternately engage oppositesides of the internal vessel wall as the vessel sinuates back and forth.This circumstance can cause the filtration/protection device to becomeat least partially collapsed between the guidewire and the internalvessel wall. This can result in at least a portion of the mouth of thedevice being closed and not fully covering the cross-section of thevessel. At least a portion of flow through the vessel can, then, bypassthe device.

At least one other circumstance might result in thefiltration/protection device becoming at least partially collapsed and acommensurate closure of at least a portion of the mouth of the device.When the guidewire carries a percutaneous transluminal coronaryangioplasty (PTCA) balloon, stent or IVUS catheter, the radial positionof the guidewire within the internal vessel can be altered from adesired generally central location. When the guidewire is displaced inthis manner, the device can become partially collapsed, as discussedabove, with commensurate partial or complete closure of the mouth of thedevice. Again, at least a portion of flow through the vessel can,thereby, bypass the device.

It is to these problems and dictates of the prior art that the presentinvention is directed. It is an improved distal protection devicedeployable in a blood vessel which facilitates maximization of desiredfiltration/protection.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a distal protectiondevice which can be deployed to fit optimally within a blood vessel orother human vasculature. Another object of this invention is to providea distal protection device having a filter basket which is maintained inthe fully opened configuration after deployment and during use. Otherobjects and advantages of the present invention will become apparentfrom the following detailed disclosure and description.

The distal protection device of the present invention is provided with aself-expanding member, shown, in one embodiment, as a loop, that createsa radial force against a vessel wall to control the lateral position ofa filter at a desired location in a blood vessel. The self-expandingloop functions to maintain open a proximal opening on a distalprotection device such as a filter basket. The loop creates a radialforce on the device's guidewire at or near the proximal end of thedistal protection device, pushing the guidewire and filter carried bythe guidewire against the vessel wall. Any debris formed as a result ofproximal intervention, such as by PTCA or stenting, is thereby caused toenter the proximal opening of the basket. Prior to the presentinvention, the guidewire could be so positioned as to keep the proximalend of the filter basket from opening fully in various tortuous anatomy,resulting in failure to capture debris intended to be captured by thebasket.

In one embodiment, the invention includes an element which serves tomaintain the filter basket, when deployed, laterally on a defined sideof the guidewire. Also included in this embodiment is a collapsible,quasi-rigid loop, or other type of spacer, carried proximate a mouth ofthe filter basket. The loop or other spacer member is positioned alongthe guidewire at or proximate the mouth of the filter basket so as toextend laterally on the same side of the guidewire as does the filterbasket. Axial alignment of the loop or spacer and filter basket isachieved, in this embodiment, by rigidly fixing the spacer to theelement which serves to maintain the filter basket on the defined sideof the guidewire, or rigidly fixing the spacer to the guidewire by aseparate securing element axially spaced from the filter basketaffixation element, but with the spacer axially aligned with the filterbasket. It will be understood that the specific loop or other spacerused is provided with a dimension on the side of the guidewire on whichit deploys sufficient so as to engage an inner surface of the vessel ata particular circumferential location and, concurrently, urge theguidewire against the inner surface of the vessel at a locationgenerally diametrically opposite that of the location engaged by thespacer.

The self-expanding loop can, as discussed above, be positioned on theguidewire at a location at or proximate the opening of the filter basketor embedded in the braid of the filter basket at or near its proximalend. It will be understood, in view of this disclosure, that theself-expanding loop or other spacer can be made, in one embodiment, toextend on the same lateral side of the guidewire as does the filterbasket even when they both rotate concurrently. This can be accomplishedby having the spacer attached to an element by which the filter basketis fixed to the guidewire, having the spacer interwoven into the mouthof the filter basket, or having the spacer tethered to the mouth of thefilter basket so that, as the filter basket moves rotationally withinthe vessel of the body, the spacer will commensurately be moved so thatsubstantial axial alignment is maintained.

The loop, while relatively rigid when expanded, is collapsible alongwith the filter basket for insertion into a delivery catheter. Insertioncan be readily accomplished by either front-loading or back-loading. Theloop expands upon deployment at a desired treatment location during amedical procedure such as a coronary intervention.

The loop can be constructed in a generally circular shape or can beformed in various “C”, “J” or spiral configurations, as desired. Acontinuous loop is preferred.

The loop may extend generally perpendicular to the guidewire whenexpanded, since, in that position, it exerts the greatest radial force,being deployed perpendicular to the vessel wall, and provides an optimalfit within the vessel. However, although perpendicular deployment ispreferred, an adequate radial force can be generated by expansion of theloop at any angle between 45 degrees and 90 degrees relative to the axisof the guidewire.

The loop can be constructed of a single small diameter wire, such as anitinol wire, or cable, coil, or stranded cable. It can be radiopaque orcovered by a radiopaque material, if desired, to enable the viewing ofthe proximal opening of the distal protection device when deployedduring a procedure.

The present invention is thus an improved apparatus for effectingoptimum functioning of a distal protection filter basket. The spacer ofthe present invention makes it likely that the proximal opening of thedistal protection device remains fully open while deployed. It expandsand positions itself upon deployment. It does not interfere with theoperation of the distal protection device, does not interfere withdebris capture, and does not interfere with blood flow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view, partly in cross section, of one embodiment of thepresent invention, the inner wall of a blood vessel shown in phantom;

FIG. 2 is a perspective view, partly in cross section, of one embodimentof the present invention, showing the filter basket within a deliverycatheter;

FIG. 3 is a view similar to FIG. 2, showing the filter basket partiallyremoved from the catheter;

FIG. 4 is a view similar to FIGS. 2 and 3, showing the filter basketfully removed from the catheter;

FIG. 5 is a view similar to FIGS. 2, 3, and 4, showing the filter basketpartially repositioned within the catheter;

FIG. 6 is a view similar to FIGS. 2, 3, 4, and 5, showing the filterbasket further repositioned within the catheter;

FIG. 7 is a view similar to FIG. 4 illustrating a distal protectiondevice, not employing the spacer in accordance with the presentinvention, deployed in a vessel traversing a tortuous course;

FIG. 8 is a view similar to FIG. 7 showing the effects of installing aspacer in accordance with the present invention;

FIG. 9 is a cross-sectional view illustrating the fitting of a loopspacer in a blood vessel;

FIG. 10 is a view similar to FIG. 9 illustrating the installation of aJ-shaped spacer;

FIG. 11 is a view similar to FIGS. 9 and 10 illustrating a C-shapedspacer;

FIG. 12 is a view similar to FIG. 8 illustrating the installation of aspiral-shaped spacer;

FIG. 13 is a view similar to FIGS. 8 and 12 illustrating theinstallation of a continuous loop spacer interwoven into the mouth ofthe filter basket; and

FIG. 14 is a view similar to FIGS. 8, 12 and 13 illustrating theinstallation of a continuous-loop spacer which is tethered to the mouthof the filter basket.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, a preferred distal protection device 10 ofthe present invention is shown in various stages of its use. FIGS. 1 and4 show device 10 in its fully deployed state. In one embodiment, basket12, which, as seen in various figures, can be generally in the shape ofa windsock, is attached to a guidewire 20, passing through a placementdevice or stop (i.e., through the lumen of a tube 18), by an element 14attaching basket 12 to guidewire 20 and holding basket 12 to preventaxial and revolutional movement with respect to guidewire 20. Guidewire20 is adapted for movement in either the distal direction, shown byarrow 24, or the proximal direction, shown by arrow 32. A ferrule 16attached at the proximal end of basket 12 can enable movement of theproximal end of basket 12 along guidewire 20 in either the distal orproximal directions, as indicated by arrows 30. When moved in a distaldirection, it can, as best seen in FIG. 1, engage stop/tube 18. It willbe understood, however, that ferrule 16 can, if desired, be axiallyfixed on guidewire 20.

A delivery catheter 22 is shown extending in the proximal directionrelative to basket 12 with guidewire 20 passing through the lumen ofcatheter 22. FIG. 4 also shows a spacer or loop 28 attached to theproximal end of basket 12 by means of ferrule 16. In such an embodiment,loop 28, along with basket 12, can concurrently float relative toguidewire 20. When ferrule 16 serves as an element to lock loop 28 withrespect to the mouth of basket 12, loop 28 is positioned so that it issubstantially axially aligned with the mouth of the basket 12. Becauseof the quasi-rigid nature of loop 28, it will have the effect of urgingferrule 16 and guidewire 20 against inner wall 36 of the vessel 38.Radial expansion of loop 28 will facilitate maintenance of the mouth ofbasket 12 fully opened.

It will be understood that, in certain embodiments, a separate element(not shown in the figures) could be used to maintain loop 28 proximatethe proximal end of basket 12 and lock loop 28 in general axialalignment with basket 12. When such a separate element is used, however,it would function to maintain loop 28 at a location about guidewire 20so that loop 28 is generally axially aligned with basket 12. Suchembodiments can permit positioning of loop 28 at a location proximallyspaced from ferrule 16. Such spacing will enable the vessel of the bodyin which the basket 12 is deployed to taper to a normal diameter if theloop 28 has caused expansion.

Also contemplated by the invention are embodiments illustrated in FIGS.13 and 14. FIG. 13 illustrates a filter basket 12 wherein the mouth ofthe basket is, in fact, defined by the loop 28. In this embodiment,strands of the basket mesh 52 are interwoven about loop 28 toeffectively integrate the loop 28 and basket 12. As loop 28 engagesinner wall 36 of vessel 38, the mouth of the basket, commensurately,occupies substantially the full cross-section of vessel 38.

FIG. 14 illustrates a basket 12 secured to guidewire 20 by means aspreviously discussed. Loop 28 is shown as being secured to guidewire 20by an element 56 spaced axially along guidewire 20 from the proximal endor mouth of basket 12. In this embodiment, element 56 may permit loop 28to revolve about guidewire 20 independently of basket 12. Tethers 54are, however, employed to maintain a substantial axial alignment of loop28 with the mouth of filter basket 12.

As will be seen, the invention contemplates a number of methods ofmaintaining a desired relationship between the spacer and the filterbasket 12. What is significant, of course, is that there be a generalaxial alignment maintained between the two.

Referring now to FIG. 2, basket 12 is shown completely enclosed withincatheter 22. In FIG. 3 movement of guidewire 20 in the distal direction,indicated by arrow 24, partially removes basket 12 from catheter 22 asshown by arrows 26. In FIGS. 5 and 6 arrows 34 show partial retractionof basket 12 and loop 28 into catheter 22 by movement of guidewire 20 inthe proximal direction indicated by arrow 32.

FIG. 7 illustrates a distal protection device basket 12 attached to aguidewire 20 extending through a tortuous path of a blood vessel. Thedevice illustrated in FIG. 7 is secured to guidewire 20 by means ofelement 14 and ferrule 16, as was described with regard to FIGS. 1-6. InFIG. 7, however, a consequence of traversing the tortuous path of ablood vessel is illustrated. As seen, the guidewire 20 will tend to takethe most direct route through the vessel and, alternatively, engagegenerally diametrically opposite sides of the inner wall 36 of thevessel 38. As will be able to be seen in viewing FIG. 7, the filterbasket 12 can become partially collapsed between the run of theguidewire 20 and the inner wall 36 of the vessel 38. The possibilitywould then exist that debris in the stream of flow could bypass thefilter basket 12.

FIG. 8 illustrates how use of a loop spacer 28 in accordance with thepresent invention overcomes this problem. Loop 28 is fixedly attached toelement or ferrule 16 so that it will be maintained on the same side ofguidewire 20 on which filter basket 12 is maintained. Because of thequasi-rigid nature of the loop 28, when it is deployed from catheter 22it will engage a circumferential point on the inner wall 36 of thevessel 38 generally diametrically opposite the point of connection atferrule 16. The rigidity of loop 28 will effectively urge guidewire 20against a circumferential point of inner wall 36, opposite the locationof engagement of the wall by the point of loop 28, distal with respectto the point of loop 28 (that is, at ferrule 16). In consequence, filterbasket 12 will be enabled to fully expand and, thereby, afford maximumprotection.

FIG. 9 illustrates, in cross-section, the functioning of loop spacer 28with respect to inner wall 36 of vessel 38. FIGS. 10 and 11 showalternative embodiments of the spacer. FIG. 10 illustrates a generallyJ-shaped spacer 40. FIG. 11 illustrates a generally C-shaped spacer 42.As will be able to be seen in view of this disclosure, in both of thesealternative embodiments, ferrule 16 and guidewire 20 will be drivenagainst inner wall 36 of vessel 38 at a circumferential locationgenerally opposite the location at which the spacer engages the wall 36.As a result, operation of the filter basket 12 will be maximized.

FIG. 12 illustrates the functioning of a spiral-shaped spacer 44.Spiral-shaped spacer 44 is shown as being connected, at a distal endthereof, to ferrule 16. Such a connection would be substantially rigidso that the orientation of spacer 44 would be at a location so as to begenerally axially aligned with the mouth of basket 12. While, inembodiments wherein ferrule 16 can float axially, spacer 44 willcommensurately be allowed to float axially, it will nevertheless bemaintained revolutionally about guidewire 20 so as to afford the desiredaxial alignment with basket 12.

FIG. 12 also illustrates another ferrule 48 which maintains the proximalend of spacer 44 at guidewire 20. It will be understood that thisferrule 48 may be permitted to float in an axial direction also or befixedly attached at guidewire 20.

It will be understood that spiral spacer 44 in FIG. 12 can also bemaintained, as is true in the case of other embodiments, rigidly withrespect to guidewire 20 by elements separate from ferrule 16. In such acase, this can be accomplished by rigidly securing the independentelements to the guidewire 20 or additionally, for example, tetheringspacer 44 to the mouth of the filter basket 28.

Other embodiments of the spacer are also specifically contemplated. Forexample, a continuous loop bent back on itself in a J-shape or C-shapeare also intended to be encompassed within the invention. Theseparticular embodiments are not illustrated in the drawing figures.

Although a preferred embodiment has been described, it will beappreciated that the description and disclosure in the instantspecification are set forth by way of illustration and not limitation,and that various modifications and changes may be made without departingfrom the spirit and scope of the present invention. Other embodimentscan also be used to effect the objects of this invention.

What is claimed is:
 1. A device comprising: a guidewire; a filter basketconnected to the guidewire, the filter basket comprising a closed distalend and an open proximal end, the distal end fixedly secured to theguidewire and the proximal end moveable along the guidewire; and aspacing member connected to the guidewire and positioned proximate tothe proximal end of the filter basket.
 2. The device of claim 1, furthercomprising a tube surrounding the guidewire and positioned within thefilter basket, the tube being configured for axial movement along theguidewire.
 3. The device of claim 2, wherein distal movement of theproximal end of the filter basket along the guidewire is limited by aproximal end of the tube.
 4. The device of claim 1, wherein the spacingmember is self-expanding.
 5. The device of claim 4, wherein the spacingmember is configured to expand independent of the proximal end of thefilter basket.
 6. The device of claim 1, further comprising a ferrule,wherein the spacing member and the proximal end of the filter basket areconnected to the ferrule, the ferrule connecting the spacing member tothe guidewire.
 7. The device of claim 6, wherein the ferrule is movablerelative to the guidewire.
 8. The device of claim 1, further comprisinga stop, wherein distal movement of the proximal end of the filter basketis limited by the stop.
 9. The device of claim 1, wherein the spacingmember defines a loop, and wherein the device further comprises at leastone axially extending tether, the tether connecting a point on thespacing member to a corresponding point on the proximal end of thefilter basket.
 10. A method comprising: inserting a catheter containinga distal protection device in a collapsed configuration into a vessel ofa patient, wherein the distal protection device comprises: a guidewire;a filter basket connected to the guidewire, the filter basket comprisinga closed distal end and an open proximal end, the distal end fixedlysecured to the guidewire and the proximal end moveable along theguidewire; and a spacing member connected to the guidewire andpositioned proximate to the proximal end of the filter basket; anddeploying the distal protection device within the vessel.
 11. The methodof claim 10, wherein deploying the distal protection device comprisesdeploying the distal protection device on a side of the vessel distal toa location affected by a medical procedure.
 12. The method of claim 10,wherein deploying the distal protection device comprises advancing thefilter basket distal to the catheter, wherein the spacing member isself-expanding.
 13. The method of claim 10, further comprising:maintaining a position of the distal protection device within the vesselduring a medical procedure; and capturing, with the filter basket,debris produced by the medical procedure.
 14. The method of claim 13,further comprising repositioning the filter basket within the catheterafter completion of the medical procedure.
 15. A device comprising: aguidewire; a filter basket connected to the guidewire, the filter basketcomprising a closed distal end and an open proximal end, the distal endfixedly secured to the guidewire and the proximal end moveable along theguidewire; and a spacing member comprising an arcuate wire extendingfrom a proximal end to a distal end, the distal end of the arcuate wireconnected to at least one of the proximal end of the filter basket orthe guidewire, the spacing member being configured to urge the guidewiretoward an inner surface of a vessel in a patient.
 16. The device ofclaim 15, wherein the proximal end of arcuate wire is connected to theguidewire, the arcuate wire forming a loop.
 17. The device of claim 15,wherein the proximal end of arcuate wire is connected to the guidewireat a position proximal to the proximal end of the filter basket.
 18. Thedevice of claim 15, wherein the arcuate wire forms a C-shaped orJ-shaped curve.
 19. The device of claim 15, further comprising aferrule, the ferrule connecting the distal end of the arcuate wire tothe proximal end of the filter basket and the guidewire.
 20. The deviceof claim 19, wherein the ferrule is movable in an axial directionrelative to the guidewire.